Cooling means for aircraft engines



Feb. 14, 1950 FQRSYTH 2,497,444

I COOLING MEANS FOR AIRCRAFT ENGINES Filed Feb. 2, 1945 4 Sheets-Sheet 1Feb. 14, 1950 FQRSYTH 2,497,444

COOLING MEANS FOR AIRCRAFT ENGINES Filed Feb. 2, 1 945 4 Sheets-Sheet 2Feb. 14, 1950 A. e. FORSYTH 2,497,444

COOLING MEANS FOR AIRCRAFT ENGINES Filed Feb. 2, 1945 4 Sheets-Sheet 3Feb. 14, 1950 A. G. FORSYTH 2,497,444

' COOLINGMEANS FOR AIRCRAFT ENGINES Filed Feb. 2, 1945 4 Sheets-Sheet 4MRQMM "changing means.

a manner as to satisfy weight and space requiremerits.

lines s of Fig. 1.

Patented Feb. 14, 1950 UNITED STATES PATENT OFFICE CO OIsING MEANS iii illcRAFT ENGINES Archibald Graham Forsyth, Cheam, England, assixnor toThe Fairey' Aviation Company Limited, Hayes, Middlesex, EnglandApplication February 2, 1945, Serial No. 575,877

This invention relates to a cooling fan ar- 'rengement for aircraftengines and thelike.

' In some types of aircraft in which a variable pitch propeller isprovided, a pitch changing mechanism is embodied in a unit disposedabout the propeller drive shaft between the front fa cing of theaircraft engine and the propeller hub structure. Such an arrangement isthe subject of several of my copending applications. Reference maybe'made, for example, to my copending application Serial No. 498,367,filed. August 12,

1943, now abandoned. f In such systems the cooling of the aircraftengine by means of cooling fans presents a problem because of thedifflculty of mounting a fan forwardly ofthe engine and connectin thefan to be driven from the propeller drive shaft. It is an object of theinvention to provide an arrangement for so mounting and driving therotor of a cooling fan, wherein there is no interference between thecooling fan and other parts positioned f'orwardly of the engine, such asthe propeller and the propeller pitch changing mechanism.

Another object of the invention is the provis sion of means for drivingthe rotor of a cooling fan, the driving means being partially enclosedwithin the same housing as the propeller pitch This is accomplished insuch These and other objects of the invention will become more apparentfrom the following descrip'tion and claims when read in conjunction vwith the accompanying drawings,- in which:

Fig. 1 is a vertical section showing one form of :the invention.

Fig. 2 is a quarter front-end view of the stator Fig. 4 is a quartersection view taken on the line i-J of Fig. l illustratingv the slippingclutches, a portion of the upper one shown bein taken on the line 4a4'aof Fig. 1'.

Fig. 5 is a quarter section view taken on the Fig. 6 is a verticalsection showing another form of the, invention, and

' Fig. 71s a front end view of the invention taken just forwardly of thepropeller hub.

One arrangement for carrying out the inventi'on isillustrated. in Figslto 5,. inclusive. With reference to Fig. I, the en ine in has a frontfacing provided with an annular bracket H to 55 30mins. (o1.ire-135.143)

which is secured by means of the bolts 12, the stator l3 of the coolingfan. The cooling fan is comprised of the stator l3 and the rotor M.

The stator 13 is preferably constructed of sheet metal and comprises anannularv rearwardly angled portion I5 provided with openings l6 At itsouter end the stator I3 is provided with a series of vanes l! as shownalso in Fig. 2f

-Disposed forwardly of and adjacent to the stator 43 is the rotor Hhaving rotor blades or vanes I 8. The manner of supporting and drivingthe rotor will be described hereinafter.

A propeller drive shaft l9 extends forwardly from 'the'front facing ofthe engine Ill. Mounted on the propeller drive shaft I9 to rotatetherewith is a propeller hub sleeve 20. This sleeve 20 has propellersockets 2t integral therewith in which are mounted the variable pitchpropeller blades 22.

The roots of the propeller blades are mounted within the sockets 2| forfull rotary movement about the longitudinal axis of the propeller bladesand the roots of the blades are provided with a has gear teeth 30' whichengage a gear 3| secured on the inner end of the worm gear 24.

The sleeve 25' has a radial flange 32 which is stepped in section andwhich is provided with two sets of gear teeth 33 and 34. The teeth 33engage a gear wheel 35 having spindle 36 mounted in bearings 31. Asimilar" gear wheel 38 has a spindle as mounted inbear'in s 40. Thisgear wheel as has gear teeth 41 which engage with the gear teeth 28 onthe sleeve 21.

The gear wheels 35 and 38 are of the same dimeter and on the same axisof rotation, but the gear wheel 35 has a greater number of teeth thanthat of the gear wheel 38. These gear wheels 35 and 38 are clutchedtogether durin pitch changing movement. The clutching means (not shown)may be of any suitable ty e, such asshown', for example, in Fig. 3 onFig. 18 ofmy 'copending application." Serial No. 498,367,.fi1e'd AugustI2, 1943. Since the specific clutching secured to the bracket means forthe two gear wheels 35 and 38 forms no part of the present invention, itis not illustrated in the drawings.

A pitch change in one direction is effected in the following manner.

Gear wheel 35 is constantly driven by the propeller drive shaft l9through the sleeve 25. When it is desired to effect the pitch change,the gear wheels 35 and 38 are clutched or dogged together so that thegear wheel 38 will rotate with and at the same speed as gear wheel 35.Since, however, the gear wheel 38 has a fewer number of teeth than gearwheel 35 it will be apparent that gear wheel 38 will rotate the sleeve21 relatively with respect to sleeve 25 and at a slower speed thusrotating the gear 38. worm 24, and effecting a pitch change. i

It will be understood that the device will embody four such sets of gearwheels 35 and 38 which are capable of being clutched together. Two ofthese sets will be similar to that just described, and the other twowill be similar but, to obtain a pitch change in the opposite'direction,the teeth on gear wheels 35 will be less in number than those on gearwheel 38.

The four sets of gear wheels are used as follows: one set is used foreffecting a pitch change at a low rate of speed in one direction: asecond, (similar but with greater difference in the teeth number) is foreffecting a pitch change in the same direction but at a greater rate ofspeed; a third is for effecting a pitch change in the opp site directionat a low rate of speed; and a fourth is for changing pitch in the samedirection as the third, but at a higher rate of speed.

Even though the aircraft engine I 8 should stop, the pitch of thepropeller blades may be feathered by means of a reversible electricmotor 42 the shaft of which carries a gear 43 which through 4 gear 44drives the pinion45. The teeth of pinion 45 engage the teeth 28 on thesleeve 21. Rota tion of the sleeve 21 and connected ring gear 29 thusrotates the gear 3|, turning worm 24 and varying the pitch of theblades.

The particular manner in which the pitch of the blades may be varied isnot essential to the present invention, although the manner described isadmirably suited to the structural arrangement of the means for drivingthe rotor |4 which will ,now bedescribed.

The teeth 34 on the flange 32 of sleeve 25 engage a. series of sixpinions 46 evenly spaced about thepropeller drive shaft l9.

Each of the pinions 46 .comprises the drive for one element of, aslipping clutch through which the rotor l4 of the cooling, fan is.driven. The

pinions 46 are provided with a central hollow tubular-hub portion 41 andare mounted for free rotation bythe spindle 48 and the two sets ofbearings 49 and 50, held in place by a spider 9 The spider 9 issecuredas a part of the housing 8 which, it will be observed, remainsstationary at all times.

Secured to the tubular hub portion 41 to rotate therewith, is a diskmember the periphery of whichis provided with radial slots 52 (see alsoFig. 4). The slots 52 slidably engage the lugs 53 which extend laterallyfrom the centrifugal weights 54 (see Fig. 4), The weights 54 aredisposed between the disk 5| and an annular ring gear member 55, thelatter having a hub 56 and a peripheral portion .51 provided with gearteeth 58. Thisperipheral portion 5'! is formed with a flange 59 which isdisposed in .the plane of the and gear member 55 so that they willrotate together.

The rotor M has a sleeve hub 62 provided on its outer surface with gearteeth 63 which are engaged by the teeth 58 of the ring gear member 55.Bearings 64 provide free rotation for the rotor hub 62 about the bracketI.

It should now be clear that as sleeve 25 rotates with the propellerdrive shaft l9, the gear teeth 34 carried by the radialfiange 32 willcause rotation of each of the pinions 46 ofthe six slipping clutches andconsequently of the disk 5| of each slipping clutch. Centrifugal forcekeeps the weights 54 outwardly and efiects a driving clutch connectionbetween the disk 5| and rear gear member 55 of each slipping clutch.Since the teeth on ring gear member. 55 engage the teeth on rotor hub62, the rotor M of the cooling fan will be rotated. I

InFigs, 6 and. 7 another embodiment ofthe invention is illustrated. Asin the first embodiment, the stator 65 is secured to the front facing ofthe engine 66 by bolts 61. The rotor 68 is secured by the bolts 69 tothe annular flange 18,01! the tubular gear member 1|. Mounted onthepropeller drive shaft 12 so asto. rotate therewith is a sleeve 13. Thetubular gear member H concentrically surrounds but is spaced from thesleeve 13 and it is mounted for relative rotation with 0 respect to thesleeve I3 by the bearings ,14 and 15.

The tubular gear member H carriesteeth 16 on, its outer surface, whichteeth engage teeth 11 on one element .18 of each of four slippingclutches. The slipping clutches are similar to those described inconnection with thefirst embodiment. They each include, aside' from theelement 18, a disk 19 with slots 80, the weights 8| with their lugs 82,the spring 83. The hub portion of the disk 19 is keyed to rotate withthehollow tubular member 84 which has an integral pinion gear 85, the teethof which enga e the teeth 86 of the sleeve gear 13. 1

It will be apparent that rotation of sleeve gear 13 bythe propellerdrive shaft 72, will rotate each of the pinions andthus rotation ofthedisks I9 of the slipping clutches. The centrifugal force of the weights8| will cause the element 18 of each clutch to rotate with its disk. 19thus driving the rotor 68 of the cooling fan.

' The slipping clutches are disposed Within a stationary housing81. Thehousing 87 has a hollow anchorage portion 83 which secures the housingagainst rotation. The housing 8'! enclosesthe pitch changing mechanismwhich will now-be described. I I

Some of the clutches for driving the rotor are connected with the pitchchanging mechanism. Viewing the upper portion of Fig. 6 it, will benoted that, mounted'within the hollow tubular member 84 for limitedaxial movement is the cylindrical rod 89. Thecylindrical rod 89 carriesthe disk 90 and the rod and disk as a unit are mounted for rotarymovement with respect tothe hollow tubular member 84, the forward endofthe cylindrical rod 89 being supported by the bearings 9I.

Keyed to the hollow tubular member 84 is a disk 92. This disk 92 hasslots 93 in which are engaged the lugs 94 of the weights 95 in a mannersimilar to that described in connection with the slipping clutchesdescribed above. The weights 95, as before, are supported by a spring96, but unlike the slipping clutches heretofore described, the weights95 have cut outs 91 in which are disposed the pivoted arms 98. The outerends of the pivoted arms 98 engage the disk 90, the purpose of whichwill be described later.

The weights 95 when in their outer position, operatively connect thedisk 92 and the clutch element 99. The clutch element 99 has a hubsleeve I which surrounds the hollow tubular member 84 and is mounted forfree rotary movement with respect thereto. The hub sleeve I00 of theclutch element 99 has a gear wheel IOI keyed to rotate therewith. Thegear wheel IN is the same diameter as the gear wheel 85, but has alesser number of teeth. This gear wheel I (H in turn engages teeth onthe flange I02 of the sleeve I03. At its forward end the sleeve I03carries a ring gear I04, the teeth of which engage the gear wheels I05of the pitch changing means in the propeller hub structure, in a mannersimilar to that described in connection with the first embodiment. Itwill be noted that housing 81 includes a web I06 provided with anopening in which the bearings I01, for supporting the sleeve hub I 00,are disposed.

The operation is as follows:

Since the hollow tubular member 84 rotates with the propeller driveshaft I2 the disk 92 of the clutch, which is keyed to the former, willalso rotate. Centrifugal force will cause the weights 95 to move totheir outermost position, thus binding, or operatively connecting thedisk 92 and the clutch element 99 to effect rotation of the latter. Thegear wheel IOI keyed to the hub sleeve I00 will then rotate at the samespeed as gear wheel 85. Since, however, it has fewer teeth than the gearwheel IOI, relative movement will be effected between sleeves I3 andI03. Sleeve I03, being connected to the ring gear I04, will rotate thelatter. As previously explained, this latter gear I04 rotates the gearsI05 and effects a change in pitch of the propeller blades.

When the pitch changing movement required has been effected, the disk 98is moved to the right in Fig. 6, thus forcing the pivot arms 98 inwardlyand. forcing the weights 95 radially inwards. This effects ade-clutching of the disk 92 and clutch element 99 so that gear wheel IOIwill be freely mounted and no pitch changing movement will take place.The disk 90 may be moved by any suitable means such as byelectro-magnets or the like (not shown). The electric wiring for theelectro-magnets may be enclosed in the anchorage 88. Theelectro-magnets, or such similar means for moving the disk 90, form nopart of the present invention but, if desired, reference may be made tomy copending application Serial No. 498,367, filed August 12, 1943,mentioned above.

It will be understood that several of such clutches may be provided(four being shown in Fig. 7). These will be foreffecting pitch changesto various pitch positions and at different speeds as referred to inconnection with the embodiment of Figs. 1 to 5, inclusive. It will beunderstood that pitch movement in the opposite direction to thatdescribed is eifected by changing the relative number of teeth on gearwheels and IN. In this embodiment a reversible electric motor may alsobe provided for feathering as in the embodiment of Figs. 1 to 5,inclusive. In accordance with the practice described in said copendingapplication, suitable limit means may be provided for stopping the pitchchange when the predetermined change has been effected.

It is apparent from the above description of the invention and itsoperation that by positioning the stator and rotor rearwardly of thefront facing of the engine, interference between the cooling fan and thepropeller or the propeller pitch changing unit is prevented, and inaddition, the cooling fan is positioned closer to the engine surfaceswhich it is intended to cool.

Some changes in structure and arrangement may be made without departingfrom the invention which should not be limited except as indicated bythe following claims.

I claim:

1. In a fan, a support having a facing, a rotatable driving elementextending from said facing, a bracket mounted on said facing and havinga bearing portion surrounding said driving element, a bladed statorcarried by said bracket, 2. bladed rotor rotatably mounted on saidbearing portion, and a power transmitting element connecting saiddriving element and said rotor, said stator and said rotor beingdisposed on one side of the plane of said facing, and said bearingportion being disposed on the other side of said plane.

2. A variable pitch propeller and fan arrangement comprising apropeller, a propeller shaft,

' propeller pitch changing mechanism surrounding said shaft, a drivingelement for said mechanism rotating with said shaft, a fixed bracketsurrounding said shaft, a fan stator carried by said bracket, a fanrotor supported by said bracket, and a connection for driving said rotorfrom said driving element for the pitch changing mechanism.

3. An arrangement as set forth in claim 2, said driving elementconsisting of a sleeve rotating with the propeller and having two setsof gear teeth integral with the sleeve, one set of said teethcooperating with said pitch changing mechanism to drive said mechanism,the other set of gear teeth serving to drive the fan rotor.

ARCHIBALD GRAHAM FORSYTH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 130,113 DuPont, Jr. Aug. 6, 1872910,760 Wood Jan. 26, 1909 1,990,979 Chilton Feb. 12, 1935 2,145,131Rhines Jan. 24, 1939 2,173,896 Caldwell Sept. 26, 1939 2,174,418 HerseySept. 26, 1939 2,274,743 Rosskopf Mar. 3, 1942 2,347,153 Hagen et alApr. 18, 1944 2,371,872 Caldwell et a1 Mar. 20, 1945 2,426,635 MercierSept. 2, 1947 2,430,225 Hagler Nov. 4, 1947 2,435,138 Heppner Jan. 27,1948 2,436,087 Benson Feb. 17, 1948 2,446,663 Palmatier Aug. 10, 1948FOREIGN PATENTS Number Country Date 560,065 Great Britain Mar. 17, 1944

